F212: Molecules, Biodiversity, Food and Health

Describe the structure and mode of action of T lymphocytes and B lymphocytes, including the significance of cell signalling and the role of memory cells

-Identiification: detect pathogen as foreign -Sending distress signals: body cell damaged by pathogens, lysosomes fight invading pathogen= damages pathogen cell = 2 effects 1. act as a distress signal and can be detected by cells from the immune system 2. act as markers to indicate that host cells is infected--> T killer cells destroy it by injected H2O2 - Antigen presenting: macrophages act like phagocytes and partially digest it, separate antigens and incorporate them into there CS molecile to become APC--> then find lymphocytes to neutralise the antigen - Instructions: communication using cytokines released from T helper cells--> stimulate B and T cells Hosts cells can release interferon which can INHIBIT VIRUS REPLICATION AND STIMULATE THE ACTIVITY OF T KILLER CELLS 1. injection of antigen or attenuated / weakened / dead / similar,pathogen; R disease 2. immune system activated / causes immune response; 3. attacked / engulfed, by, phagocytes / macrophages; 4. ref antigens presented; 5. selection / production, of active T, cells / lymphocytes; 6. T cells, clone / divide / mitosis; 7. secretion of cytokines; 8. activation of B cells; 9. B cells, clone / divide / mitosis; 10. production of, plasma / effector, cells; 11. production of antibodies (by plasma cells); 12. production of memory cells; 13. memory cells remain in body; 14. (secondary) response to infection quicker; 15. (secondary) response to infection greater; 16. no symptoms when infected / AW Importance of B memory cells for immunity • produced during primary response • remains in the body • specific to antigen • produce secondary response • more quickly • divide to make plasma cells • manufacture antibodies • more antibodies made • give long term immunity T helper cells o secrete interleukins; o (this) induces antibody formation by plasma cells/descendents of B-cells; o (this) stimulates the multiplication of killer T-cells; o (and) the differentiation of more killer T-cells (at the site of infection) • cytokine / interleukin / receptor has, specific / unique, shape ; • (cytokine / interleukin), binds / attaches / bonds to / fits into, receptor ; • receptor on (cell surface) membrane (of B lymphocyte) • (receptor and cytokine have) complementary shapes • activates/ stimulates, clonal expansion / mitosis

Outline, with the aid of diagrams, how DNA replicates semi-conservatively, with reference to the role of DNA polymerase

1. / unwind 2. unzip / described; 3. H bond breaks; 4. both strands act as template; 5. (aligning of) free (DNA) nucleotides 6. complementary, base / nucleotide, pairing; 7. C to G and T to A / purine to pyrimidine; 8. hydrogen bonds reform; 9. sugar-phosphate back bone forms; 10. (using) covalent / phosphodiester, bond; 11. semi-conservative replication; 12. DNA polymerase; 13. ligase / helicase / gyrase used in correct context a. C - G 3 H bonds / T - A 2 H bonds b. activation of free nucleotides (with 2 phosphates)

Describe how the effects of pH on enzyme activity can be investigated experimentally

1. A starch-agar plate is made up by mixing starch with agar. 2. The mixture is poured into a petridish and left to set. 3. It forms a semi-rigid gel in the plate. 4. Cut wells into each plate using a cork borer 5. Into each well place the same volume of a different pH buffer solution 6. Into each well except one, place an identical volume of stock amylase solution 7. Into the well without the amylase, add an equal volume of distilled water as a control 8. Incubate for 24h in a dry oven at 35˚C Flood the plate with an iodine solution and rise with water 9. Measure the diameter of the cleared zone- this gives an indication of how much substrate has been turned into product

Differences between starch and glycogen

1. Made up of α Glucose Energy storing molecules 2. They do not dissolve, so the stored glucose does not affect the water potential of the cell. This features is vital in both plants and animals, as glucose stored in a cell as free molecules would dissolve and dramatically reduce the water potential 3.They hold glucose molecules in chains so that they can easily be broken off from the ends to provide glucose for respiration when required insoluble ; does not , change / affect , water potential / Ψ , of cell ; can be , broken down / hydrolysed / built up , quickly / easily ; lots of branches for enzymes to attach ; compact ; (therefore) high energy content for mass / energy dense / AW ;

Describe how the effects of temperature on enzyme activity can be investigated experimentally

1. Take samples of potato tissue (containing catalase) using a cork borer then stick into discs of equal thickness 2. Place an equal number of discs in each of seven tissues and place one in each of a range of water baths from 20-80˚C 3. Place an equal volume of pH 7 buffer and hydrogen peroxide into each of sever separate test tubes and place one in each water bath. 4. Allow to equilibrate. 5. Taking each in turn, add peroxide/buffer mixture to the potato discs, then fix a stopper and a side arm into the tube. Close the clip. 6. As oxygen gas is produced in the reaction it pushes the water bubble along the side arm. 7. Time how long it takes for the bubble to move 5cm.

Describe how the concentration of glucose in a solution may be determined using colorimetry

1. Using standard / known, concentration (of reducing sugar) 2. Heat with Benedict's solution 3. Use excess Benedict's solution 4. Solution turns from blue, to green / yellow / orange / brown / brick red. 5. Remove the precipitate 6. Calibrate the colorimeter to zero 7. Using a blank / water / unreacted Benedict's solution 8. Use red / orange filter 9. Read the transmission / absorbance 10. More transmission / less absorbance = more sugar present 11. Obtain a calibration curve 12. By plotting the transmission / absorbance against sugar concentration 13. Carryout a reading for the unknown concentration of sugar 14. Read the concentration of the graph using the transmission / absorbance reading 15. If using a non- reducing sugar then follow procedure to obtain a reducing sugar before heating with Benedict's.

Outline how variation, adaptation and selection are major components of evolution

1. Variation must exist 2. Environment selects individuals whose variations give them an advantage 3. Individuals with the advantage survive and reproduce 4. They pass on the advantageous variations 5. The next generation are better adapted to the environment. Group of individuals within a species will evolved into a new, different species. This may occur if: • A population of the species migrates to a new environment • An environmental change affects only some populations of the species • Reproductive barrier: prevents some populations of the species to interbreed, these populations then evolve along different paths according to their local environment and these changes cannot be passed to the rest of the species

Compare and contrast the five kingdom and three domain classification systems

5 Kingdoms system • Bacteria and Archaea in separate domains 3 domain system • Bacteria and Archaea in Kingdom Prokaryota 3 Domains: 1. Bacteria: unicellular prokaryotic 2. Archea: unicellular prokaryotic 3. Eukaryota (protista): unicellular and multicellular, eukaryotic Bacteria is different from Archaea and Eukaryotae • Different cell membranes • Different internal structures to flagella • Different enzymes (RNA polymerase) for building RNA • Different mechanisms for DNA replication and building RNA Archaea and Eukaryotae • Similar enzymes (RNA polymerase) for building RNA • Similar mechanisms for DNA replication and building RNA 1. scientific knowledge changes as new discoveries are made / AW; 2. technological developments lead to new discoveries; 3. named technological development; e.g. microscopes, new DNA technology ref. (legitimate) differences of opinion amongst biologists/scientists /taxonomists; 4. ref. true bacteria (bacteria) and archaea; 5. ref. differences between bacteria and archaea; e.g. different RNA polymerase, membrane structure, flagellae, histone 3 domains AND 5 kingdoms domains are, bacteria / eubacteria, AND, archaea / archaebacteria, AND, eukarya / eukaryotes ; kingdoms are prokaryotes AND protoctists AND fungi AND plants AND animals eukaryotes split into different kingdoms / all eukaryotes are in the same domain ; all prokaryotes are in the same kingdom / prokaryotes split into different domains ; domain classification based on, rRNA / ribosomes / RNA polymerase / protein synthesis / enzymes / flagella / membrane structure ;

Define the term balanced diet

A diet that contains all the nutrients of the nutrients requires for health and growth.

Define the term species

A group of individual organisms which are similar in appearance, physiology, biochemistry and genetics whose members are able to interbreed freely to produce fertile offspring

Outline the significance of both high and low values of Simpson's Index of Diversity (D)

A high value indicates a diverse habitat. The habitat tends to be stable and able to withstand change A low value indicated a habitat dominated by a few species. A small change could damage or destroy the whole habitat

Describe the advantages and disadvantages of using microorganisms to make food for human consumption

Advantages - Production of protein can be many times faster than that of animal or plant protein - Production can be increased or decreased according to demand - No animal welfare issues - They provide a good source of protein for vegetarians - The protein contains no animal fat or cholesterol - Single-cell protein production could be combined with removal of waste products Disadvantages - Many people may not want to eat fungal protein that has been grown on waste - The microorganisms are grown in huge fermenters and need to be isolated from the material on which they grow - The protein has to be purified to ensure it is uncontaminated - The conditions needed to grow the useful organisms are ideal for pathogenic organisms. Care needs to be taken to ensure that the culture is not infected - The protein does not have the taste or texture of traditional protein sources advantages 1. A1 low in , saturated fat / cholesterol ; ora 2. A2 less likely to cause , heart disease / atherosclerosis / AW ; 3. A3 no / fewer , animal welfare / moral / ethical / religious, issues ; 4. A4 source of essential amino acids ; 5. A5 high rate of (protein) production ; 6. A6 idea of fewer energy losses / more energy efficient ; 7. A7 idea that production can be changed more easily (according to demand) ; 8. A8 idea that cheaper to produce (once established) ; 9. A9 uses less , land area / space ; 10. A10 (might be) grown on (plant) waste ; 11. A11 less risk of transfer of disease from animals 12. A12 can be produced in any , climate / season disadvantages 1. D1 different , taste / texture / palatability ; 2. D2 lacks / less , iron 3. D3 needs to be processed (to add ,taste / texture) ; 4. D4 idea of consumer resistance ; 5. D5 growth conditions suit , pathogenic / harmful / spoilage , microorganisms / bacteria / microbes ; 6. D6 need for , isolation / purification (of proteinfrom material on which they grow) ; 7. D7may require removal of , toxins / (excess) RNA ; 8. D8 loss of farming jobs 9. D9 idea of higher set up costs ; low(er) / less, energy (than beef) ; useful for, slimming / weight control / AW ; low(er) / less, (total) fat ; (very) low / (much) less, saturated fat ; lower, cholesterol OR lower risk of, (coronary) heart disease / CHD / cardio-vascular diseases / heart attack / cardiac arrest / myocardial infarction / MI / angina / ath erosclerosis / atheroma / stroke / hypertension ; contains carbohydrate / AW ; low(er) / less, iron content ; (increased risk of) anaemia / fewer RBCs / less haemoglobin / reduced oxygen carrying capacity of blood ; low(er) / less, protein ; (mycoprotein provides) more balanced diet ; need larger intake to meet requirements / AW ;

Discuss the consequences of global climate change on the biodiversity of plants and animals, with reference to changing patterns of agriculture and spread of disease

Agriculture - Global warming causes increased temperature 1. Pests • Pests are not killed during the winter because the temperature is warmer • The seasons are longer for pests and diseases to build up 2. Crops • Longer growing seasons • Growth rate increases with the higher temperature • Newer/earlier-growing crops are possible 3. Exotic animal diseases are possible e.g. blue tongue 4. Raised sea level • Erosion • Flooding of low-lying agricultural land • Salination ruins soil for growing Disease - Global warming causes increased temperature 1. Current diseases • Pathogens are not killed because the climate is warmer • Therefore, there is a larger pathogen population 2. Exotic diseases • Vectors of disease are able to survive, including -Malaria in the Anopheles mosquito -Yellow fever in the Aedes mosquito -Sleeping sickness in the Tsetse fly Climate change forces migration which can be damaging because: • Into farmers land • New predators • New diseases • New pests • Loss of food • Out of protection zones • Out of space Effects of climate change on Agriculture • Increase growing season • Increase growth • Increase CO2 = increases photosynthesis • Different rain patterns • Increases evaporation = increases rainfall • Increases sea levels = decreases land for crops • Farmers need to change crops • Change farming methods Diseases • Increasing growing season also increases populations of pests • New pests and diseases in an area.

Explain the importance of sampling in measuring the biodiversity of a habitat

Although sampling causes disturbance to habitats, it is important to sample areas. • Human activities affect the environment in a number of ways • Unless we study how our activities affect our environment, we cannot assess the effect we have. Environmental impact assessments (EIAs) are a very important part of the planning process • EIAs are used to estimate the effects of a planned development on the environment

Compare and contrast the structure and functions of starch (amylose) and cellulose;

Amylose Made up of α-glucose Straight chain Tends to coil up Plant storage polysaccharide Cellulose Made up of β-glucose In a chain, alternate glucose subunits are inverted Forms straight chains The β-glycosidic bond can only be broken down by a cellulose enzyme, which herbivors have, but humans do not Forms plant cell walls

Describe how random samples can be taken when measuring biodiversity; in animals and in plants

Animals Sweet net dea of: unbiased method to selecting sampling area ; sample many times / AW, and calculate mean / average ; standardised sweeping procedure ; ensure insects do not escape (before being identified) ; method to prevent recounting ; sample at different times of, day / month / year / weather conditions ; Collecting from trees Pitfall trap Tullgren Funnel Light trap • idea of:unbiased method to selecting sampling area; • sample many times / AW, and calculate mean / average ; • standardised sweeping procedure ; • ensure insects do not escape (before being identified) ; • method to prevent recounting ; • sample at different times of, day / month / year / weather conditions ; Plants • Measuring distribution and abundance of an area • use grid and random numbers to generate co-ordinates • throwing keys biased ; AW • use of quadrat; e.g. 50 cm × 50 cm • ref to how quadrat is placed; R random • identify species/use of keys • count number of plants / percentage cover of plants • estimate, percentage cover / abundance ; • point (frame) quadrat - ensure that bare ground is also recorded • Record in a table • may be single plants in some samples and many in others ; • bigger study area / more data ; • improves reliability / AW ; • record other plants ; • measure / note, abiotic variables ; A example 1. tape measure / rope, laid 2. line / belt, transect ; 3. continuous / interrupted / AW ; 4. (use quadrat to) record percentage cover of plants ; 5. (use quadrat with) ACFOR scale ; 6. point quadrat use described ; 7. use of key to identify species ; 8. data recording sheets prepared in advance ; 9. QWC - sequencing of steps in procedure

Describe how the effects of substrate concentration on enzyme activity can be investigated experimentally

As before, but keeping the temperature and the number of potato discs the same and changing the volume of hydrogen peroxide in each test tube

Describe and explain the effects of enzyme concentration on enzyme activity

As enzyme concentration increases, the rate of reaction increases linearly as there are more active sites are available, until the substrate concentration becomes a limiting factor and the rate stops increasing enzyme concentration ~(3 max) 1. reaction (rate) increases with increased enzyme; high / low 2. more active sites available; 3. in excess substrate / as long as enough substrate (molecules available to occupy active site); 4. (as reaction progresses) the rate will decrease as substrate, used up / becomes limiting; R plateau

Describe and explain the effects of substrate concentration on enzyme activity

As the substrate concentration rises, the rate of reaction rises because there are more substrate molecules to react. At higher concentrations, all of the active sites become filled, so the rate of reaction remains the same substrate concentration ~(3 max) 5. reaction (rate) increases with increased substrate; A high / low 6. more, molecules available to enter active site / ESC formed A more successful collisions 7. reaches point where all active sites occupied; 8. no further increase in rate / reaches Vmax; Aplateau / levels off 9. enzyme conc. becomes limiting / unless add more enzyme;

selective pressure

Avaliability of food predators disease physical and chemical factors

Outline possible new sources of medicines, with reference to microorganisms and plants and the need to maintain biodiversity

Because there are many species of drugs in the tropical rainforest that are yet to be discovered, it is hoped that there are many new medicinal drugs yet to discover. But biodiversity needs to be maintained- plants with medicinal properties should be farmed sustainably so that the species is not wiped out. Research has been undertaken into the way that microorganisms cause disease. Many use receptors on heir plasma membranes. The receptor sites can be blocked by a drug, and then the disease-causing pathogen cannot gain access to the cell. • By accident, traditional medicines, observation of wildlife, modern research

Outline the behavioural, physiological and anatomical (structural) adaptations of organisms to their environments

Behavioural • Bird migration to find food • Bird song to attract mates • Burrowing of desert animals to escape the heat of the day Physiological • Camel kidneys produce very concentrated urine to reduce water loss • Stomata open and close in response to light intensity and water availability Anatomical • Flagella to aid movement • Venomous glands in scorpion tails for self defence • Blubber in marine animals for buoyancy and insulation • Large ears on bats to aid echo location • Thorns on plants to reduce predation XEROPHYTES Behavioural • Some plants close their stomata when little water is available • Some plants only open their stomata at night to conserve water • Some plants fold/roll their leaves to trap moist air close to the stomata, to reduce the water vapour potential gradient • Some plants open the stomata when short of water to make their leaves wilt, exposing less surface area to the sun Physiological • Some cacti have an accordion-fold structure, enabling them to absorb more water in the dry periods Anatomical • Shallow roots spread over a wide area • Long roots • Fleshy stems to help store water • Small leaves to reduce the evaporation surface area • Waxy leaves to reduce water loss • Curled, folded, hairy leaves or sunken stomata to reduce water loss by transpiration

Discuss the importance of international co-operation in species conservation with reference to The Convention in International Trade in Endangered Species (CITES)

CITES aims to: • Regulate and monitor international trade in selected species of plants and animals • Ensure that international trade does not endanger the survival of populations in the wild • Ensure that trade in wild plant is prohibited for commercial purposes • Ensure that trade is artificially propagated plants is allowed, subject to permit • Ensure that some slightly less engendered wild species may be traded subject to a permit, as agreed between the exporting and importing countries How CITES saving endangered animals • Ban on killing animal • Ban on trading animal • Increased cooperation between countries • Education • Permits issued CITES 2 max • regulate / monitor / prevent , trade in , selected / certain / endangered , species ensure (international) trade does not endanger , wild populations / AW ; • prohibit (commercial) trade in wild plants ; • allow trade in , artificially propagated plants / AW ; • allow (some) trade in less endangered , wild species / organisms / animals and plants ;

Describe the differences between continuous and discontinuous variation, using examples of a range of characteristics found in plants, animals and microorganisms

CONTINUOUS VARIATION 1. no defined categories ; 2. range of values / intermediate values ; 3. influenced by, environment / many genes / genes and environment ; 4. quantitative / has to be measured / cannot be counted DISCONTINUOUS • single / few, genes; • qualitative; • discrete categories / either low or high resistance / • no intermediates; • no / small / little, environmental effects

Explain the importance of cofactors and coenzymes in enzyme-controlled reactions

Cofactors Ions increase the rate of enzyme-controlled reactions. Their presence allows enzymesubstrate complexes to form more easily. (acts as a) cofactor ; (Cl - ) binds to, enzyme / amylase / amylose / substrate ; enzyme substrate complex / ESC, forms more, easily / quickly Coenzymes Small, organic, non-protein molecules that bind for a short period of time to the active site. They may bind just before, or at the same time, as the substrate binds. In many reactions, coenzymes take part in the reaction, and like substrate, are changed in some way. Unlike the substrate, coenzymes are RECYCLED back to take part in the reaction again. The role of coenzymes is often to carry chemical groups between enzymes so they link together enzyme-controlled reactions that need to take place in sequence. Some coenzymes are permanent parts of the enzymes- prosthetic groups. These contribute to the shape of the enzyme.

Discuss what is meant by the terms disease

DISEASE: A DEPARTUR FROM GOOD HEALTH caused by a malfunction of the mind and body

Compare and contrast the primary and secondary immune responses

DOESNT START IMMEDIATELY BECAUSE time taken for • antigen presentation/AW; • clonal selection/AW; • clonal expansion/AW; • differentiation (of B cell into plasma cell); • production of antibodies; • there are no memory cells Importance of B memory cells for immunity • produced during primary response • remains in the body • specific to antigen • produce secondary response • more quickly • divide to make plasma cells • manufacture antibodies • more antibodies made • give long term immunity 1st injection • antigens on the dead pathogen detected by (T/B) lymphocytes; • specific B lymphocytes clone/divide rapidly by mitosis; • plasma cells released to blood; • plasma cells secrete antibody into blood; • levels fall once all antigens are destroyed Primary response When the infecting agent is first detected, the immune system starts to produce antibodies, but it takes a few days before the number of antibodies in the blood rises to a level that can fight the infection Secondary immune response The immune system recognises the pathogen if the body is infected again, so the immune system can swing into action more quickly. The production of antibodies rises sooner and reaches a higher concentration

Explain the consequences of the four observations made by Darwin in proposing his theory of natural selection

Darwin's four observations were: 1. Offspring appear genetically similar to their parents 2. No two individuals are identical 3. Organisms have the ability to produce large numbers of offspring 4. Populations in nature tend to remain fairly stable in size These observations led him to the conclusions that - There is a struggle to survive - There is competition for survival -Better adapted individuals survive and pass on their characteristics - Individuals show variation -Over time, a number of changes may give rise to a new species -Characterisitcs can be inherited by offspring 1. Due to selective pressures 2. 2 individuals reproduce and pass the alleles on 3. Reproduce over a number of generations

Use a dichotomous key to identify a group of at least six plants, animals or microorganisms

Dichotomous: branching resulting in multiple options The key provides a series of questions which have two answers, usually 'yes' or 'no'. The answer to each question leads you to another question. Eventually the answers will lead you to the name of the species. A good dichotomous key has one less question than the number of species it can identify.

Discuss the possible links between diet and coronary heart disease (CHD)

Dietary factors that increase the chances of CHD: EXCESS SALT: Excess salt in the diet decreases the water potential of the blood. As a result, more water is held in the blood and blood pressure increases. This can lead to hypertension, which can damage the inner lining of the arteries, which is one of the early steps in the process of atherosclerosis Excess saturated fats: Saturated fats can cause damage to the heart 45-47% of deaths from cholesterol have been linked to high blood cholesterol levels Excessive alcohol consumption High blood cholesteroL • CHD is a disease of the coronary arteries which damages or causes malfunctions of the heart. It is caused by atherosclerosis. o Narrows the size of the lumen o Restricts the blood flow to the heart muscle, which can cause oxygen starvation • Atheroscleosis: the process of deposition of fatty materials (notably cholesterol) in the lining of arteries to from atheroma. It leads to arteriosclerosis (hardening of the arteries)

Describe the classification of species into the taxonomic hierarchy of domain, kingdom, phylum, class, order, family, genus and species

Domain Kingdom Phylum Class Family Genus Species We classify to: • Make study easier • Make it easier to identify organisms • Help us see relationships . As you rise through the ranks of taxa, the individuals grouped together show more and more diversity. There are fewer similarities and the individuals are less closely related • (information used to) decide which, group / taxon, organism / species / named example, fits in • compare the proportion of (different) bases • compare the DNA / genes / sequence of bases • idea of: the more similar the, DNA / genes, the closer the relationship / AW ; based on (differences in) , DNA / RNA / nucleic acids / polynucleotides ; idea that more accurately reflects origins (of, prokaryotes / eukaryotes) ; (domain) divides / AW , prokaryotes ; ora idea that domain reflects differences / AW , between (eu)bacteria and archaea ; example of two differences to support point 3 or 4 ; (domain) groups / AW , eukaryotes together ; ora idea that domain reflects the fact that there are similarities between eukaryotic kingdoms ; example of two or more similarities to support point 6 or

Discuss the fact that classification systems were based originally on observable features but more recent approaches draw on a wider range of evidence to clarify relationships between organisms, including molecular evidence

Early classification systems were based on observable features i.e. appearance and anatomy. However, this made it easy to make mistakes. Therefore, early classifications have been adapted and made more accurate as more research is done and more information is made available e.g. advances in physiology and biochemistry. Cytochrome C analysis Cytochrome C is a respiratory protein that varies in different species. The sequence of amino acids can be analysed and compared. • If the sequence is the same, the two species must be closely related • If the sequence is different, the species are not closely related. The more differences there are, the less closely related the two species area. DNA/RNA analysis The sequence of bases in organisms' DNA or RNA can be analysed similarly - the more similar the sequences, the more closely related the species area. Changes in protein/base sequence are as a result of random mutation - more differences imply more mutations.

Discuss the significance of environmental impact assessments (including biodiversity estimates) for local authority planning decisions.

Environmental Impact Assessment -EIA • Avoid/minimise adverse effects on biodiversity of an area • Take into account potential environmental consequences • Consultations and exchange of information with partner states • Notification of procedures to partner states • Emergency responses for danger to biodiversity An EIA is undertaken depending on: • The size of the development • The environmental sensitivity of the area • Types of expected impacts 3 procedures when creating an EIA 1. Assessment of the local biodiversity and effect of the development 2. Publish the assessment 3. Considered before any planning decision Benefits • Problems are identified at an early stage and can be dealt with • Improves environmental acceptance • The biodiversity of the area • Considerations of the conservation needs of the area • Consideration for any endangered species and their conservation needs, or any laws covering the protection of endangered species. • Planning authorities use it to make an informed decision about protection needed during or after the development has taken place. Role: 1. Ref. biodiversity values and need for conservation 2. Ref to endangered species and need for protection 3. Ref to laws concerning endangered species 4. Ref to planning agreement e.g. translocation of species biodiversity (of heathland) ; rare / endangered, species / plants / animals / fungi / organisms / named organism ; rarity of (this) habitat ; example of current legal status ; (likely) reduction in size of, habitat / ecosystem / heathland ; effect of reduced size on viability (of whole ecosystem) ; effect on, movement / spread, of, species / named species / plants / animals ; a method of minimizing impact / AW / named example

Evaluate the epidemiological and experimental evidence linking cigarette smoking to disease and early death

Epidemiological • A regular smoker is three times more likely to die prematurely than a non smoker • 50% of regular smokers are likely to die of a smoking related disease • The more cigarettes a person smokes per day, the more likely (s)he is to die prematurely, and the younger (s)he is likely to die • A smoker is 18x more likely than a non-smoker to develop lung cancer 25% of smokers die of lung cancer • A heavy smoker (25+ cigarettes per day) is 25 times more likely to die of lung cancer than a non-smoker The chance of developing lung cancer reduces as soon as a person stops smoking • Chronic Obstructive Pulmonary Disease is rare in non-smokers 98% of people who have emphysema are smokers 20% of smokers have emphysema • It is not easy to link smoking with cardiovascular diseases because there are so many other factors that can contribute to cardio-vascular disease. Experimental • In the 1960s there were experiments on dogs. o Some dogs were made to breathe smoke from unfiltered cigarettes. They developed changes in their lungs that were similar to those of Chronic Obstructive Pulmonary Disease. They also developed early signs of lung cancer some dogs were made to breathe smoke from filtered cigarettes. These doges remained healthier, but their lungs still showed early signs of lung cancer

Discuss current estimates of global biodiversity

Estimates of global biodiversity can never be accurate because: 1. We cannot be sure we know all the species on Earth 2. New species are continually discovered 3. Evolution and speciation are continuing 4. Many species are becoming extinct not all , areas explored / species yet discovered ; microscopic / small / nocturnal / camouflaged , species difficult to see ; sampling might miss rare species ; organisms mistakenly identified as one species may actually be two (or more) species ; concept of species is difficult to define

Describe how the use of fertilisers and pesticides with plants and the use of antibiotics with animals can increase food production

Fertilisers: Replace minerals in the soil which may have been removed by the previous crops. They contain Nitrate, Phosphate and Potassium. They increase the rate of growth and the overall size of crops Pesticides: Kill organisms that cause diseases in crops. These organisms would reduce yield or kill the crop. Many crops are sprayed with fungicides to reduce fungal growth in the leaves or roots. Sheep are dipped to kill ticks. Antibiotics: Infected animals can be treated with antibiotics to reduce the spread amongst animals that are intensively farmed in close proximity to each other. Such diseases could reduce the growth performance of the animals and may impair reproduction. 1. reduces / prevents (infectious) disease ; 2. prevent, problems / named problem, with gut ; 3. digest food more, efficiently / easily / quickly ; 4. greater proportion of, food / energy, can contribute to growth 5. reduce risk of transmitting, pathogens / named pathogen, to humans

Describe, with the aid of diagrams, the formation and breakage of glycosidic bonds in the synthesis and hydrolysis of a disaccharide (maltose) and a polysaccharide (amylose)

Formation Water is eliminated as the -OH from one glucose and the -H from an -OH from the other leave. This means that the remaining O joins to the C on the other glucose making a disaccharide Breaking Water is used to break the glycosidic bond between the subunits. The -H returns to the O and the -OH returns to C4 In polysaccharides, there are many glucose subunits joined together by 1,4-glycosidic bonds.

Define the term speciation

Formation of a new species

Discuss the evidence supporting the theory of evolution, with reference to fossil, DNA and molecular evidence

Fossils • Similarities found between living species and fossils • The fossil of Archaeopteryx (earliest known bird) clearly has both bird and reptilian features, explain the link between birds and reptiles. fossils show that organisms have changed over time organisms idea that fossils or rocks can be dated idea of fossils showing intermediate forms / sequences Problem with fossil evidence • Fossil evidence is incomplete • They only form under certain conditions • After being formed they can still be damaged or destroyed by rock movement DNA • Genes can be compared by sequencing the bases in the DNA • This shows how closely related species are and therefore how recently they became new species Molecular evidence • Cytochrome C is a protein that enables ATP to be made in oxidative phosphorylation • Similarities in this molecule shows how closely related two species are

Explain both genetic and environmental causes of variation

Genetic causes • Mutations • Meiosis does not produce genetically identical individuals • Random mating and random fertilisation of gametes Environmental causes • Availability of nutrition • Exposure to light • Strong winds • Drought Genetic Our genes define our characteristics, and the combination of alleles that we inherit from our parents is unique. Unless a person has an identical twin, there is only a remote chance that someone will have the same combination of alleles, which means that everyone's characteristics are unique Environmental Many characteristics can be affected by the environment- if a tree that would normally grow to 6m was planted where there was little soil or water, e.g. a rock crevice, it might only grow to 1.5m. If a pet was overfed, it would become obese.

Discuss what is meant by the terms health

HEALTH: is a state of mental, physical and social well being not only being free of disease

Compare the structure and function of haemoglobin (as an example of a globular protein) and collagen (as an example of a fibrous protein)

Haemoglobin Globular protein Soluble in water Wide range of amino acid constituents in primary structure Contains a prosthetic group- a haem Much of the molecule is wound into alpha-helix structures Collagen Fibrous protein High proportion of glycine Insoluble in water Approx. 35% of the molecule's primary structure is glycine Does not have a prosthetic group Much of the molecule consists of left-handed helix structures Similarities (collagen has) •amino acid, chain/ sequence; •peptide bonds ; •helical / helix ; •3 bonds / interactions from: disulfide / ionic / hydrogen / hydrophobic or hydrophilic ; •quaternary structure ; •more than one polypeptide / subunit;

Discuss the possible effects of a high blood cholesterol level on the heart and circulatory system, with reference to high-density lipoproteins (HDL) and low-density lipoprotein (LDL)

High Density Lipoproteins • Carry cholesterol back from the body tissues to the liver • Liver cells have receptors which allow the HDLs to bind • HDLs are used by the liver to make bile • High levels of HDLs in the blood are associated with lowering blood cholesterol • HDLs reduce deposition in the artery walls -atherosclerosis • HDLs may even remove fatty depositions -atherosclerosis • As HDLs are formed from unsaturated fats, unsaturated fats are thought to be healthier Low Density Lipoproteins • Carry cholesterol from the liver to body tissues • Tissue cells have receptors which allow the LDLs to bind • High levels of LDLs in the blood are associated with increasing blood cholesterol • Saturated fats are thought to decrease the effectiveness of LDLs receptors, therefore increasing the concentration of cholesterol in the blood • Unsaturated fats are thought to increase the effectiveness of LDLs receptors, therefore decreasing the concentration of cholesterol in the blood • Polyunsaturated fats are thought to remove LDLs from the blood 1. damage to endothelium; 2. LDLs contain, saturated fat / cholesterol; 3. LDLs collect at site of damage; 4. fatty substances / cholesterol / LDLs, deposited, in artery wall / under endothelium; 5. high level of saturated fat in diet; 6. animal fat / red meat / dairy products; 7. high cholesterol (in blood / body); 8. lack of, vitamin E / antioxidants; 9. high salt in diet; 10. obesity linked to, high blood pressure / hypertension; 11. damage to artery, walls / endothelium; 12. cholesterol transported in lipoproteins; 13. cholesterol deposited in artery walls; 14. in coronary arteries; 15. atherosclerosis/ atheroma; 16. formation of, plaques / fatty streaks; 17. hardening / loss of elasticity (of artery wall); 18. roughens lining / increases friction; 19. clot formation / thrombosis / thrombus; 20. narrows / restricts, lumen; 21. reduced / restricted, blood flow / oxygen, to heart muscle 22. heart (muscle), under stress / works harder; 23. angina / heart attack / myocardial infarction / heart failure /hypertrophy; R CHD

Define the terms immune response, antigen and antibody

IMMUNE RESPONSE: The specific response to a pathogen, which involves the action of lymphocytes and the production of antibodies ANTIGEN: Molecules that stimulate an immune response ANTIBODY: Protein molecules that can identify and neutralise antigens Difference between antibiotic and antibodies 1. antibiotic is produced by microorganisms/fungi/bacteria; 2. will kill/inhibit the growth of other microorganisms; 3. antibodies are produced by cells/B-lymphocytes of the immune system; 4. bind specifically to pathogens/bacteria/viruses causing their destruction; 5. antibiotics are non-protein chemicals, antibodies are protein/gamma-globulins

Describe the conservation of endangered plant and animal species, both in situ and ex situ, with reference to the advantages and disadvantages of these two approaches

In situ: Species are protected in their natural environment Advantages -Species are in their natural environment -Facilitates scientific research -Maintain and restores environmental integrity -Permanently protects natural and cultural heritage -Permanently protects biodiversity and ecosystems Disadvantage -Land is important for traditional hunting and religious reasons -Protecting animals that may migrate and raid nearby farms and destroy crops -Tourists may feed protected animals or litter -May lead to illegal hunting or harvesting Ex situ: Species are removed from their natural habitats to be conserved [Animals] Advantage -Breeding programs -Repopulate areas by reintroduction -Health can be maintained by vets -Protected from hunting and predators Disadvantage -Expensive -Animals fail to breed due to being outside of their natural habitat -Limited space= limits population size= decreases genetic diversity -Little genetic variation -Loss of natural instincts for food and survival Management problems • capture of species/AW; • numbers of species caught ref to extinction; • ref to named example e.g. elephants; • maintenance of genetic variability/gene pool; • ref to funding; • ref to species ownership/AW; • problems of storage and maintenance; • ref to specific example of problem; e.g. inbreeding/altered breeding/seed preparation;

State the structural difference between alpha- and beta-glucose

In α-glucose the -OH on carbon 1 is below the plane of the ring. In β-glucose it is above the chain of the ring.

Describe, with the aid of diagrams, the structure of a collagen molecule

Made up of three polypeptide chains, each about 1000 amino acids long, wound around each other. Hydrogen and covalent bonds (cross links) form between the chains. The cross links are staggered to make the molecule stronger 1. amino acids / glycine, small (to allow close packing);the small one is, every 3rdamino acid / at every level in the molecule; 2. chains ,form a tight coil / lie close to each other; 3. held together by hydrogen bonds; 4. bonds form between R groups of lysines; 5. molecules form, fibres / bonds with adjacent molecules; fibril 6. covalent bond between, adjacent molecules / CO-NH groups; 7. fibres composed of parallel molecules; 8. ends of parallel molecules staggered; 9. prevents line of weakness

Describe the causes and means of transmission of malaria, AIDS/HIV and TB

Malaria 1. If the host already has malaria, the female anopheles mosquito will suck the parasite gametes into its own stomach 2. The gametes fuse and the zygotes develop in the mosquito's stomach 3. Infective stages are formed and these move to the mosquito's salivary glands 4. When the mosquito bites another person, it injects a little saliva as an anticoagulant 5. The saliva contains the infective stages of the parasite 6. In the human host, the infective stages enter the liver where they multiply before passing into the blood again 7.In the blood they enter red blood cells, where the gametes are produced HIV/AIDS The virus enters the body by : 1. Exchange of bodily fluids such as blood to blood contact 2. Unprotected sexual intercourse 3. Unscreened blood transfusions 4. Use of unsterilised surgical equipment 5. Sharing hypodermic needles 6. Accidents such as 'needlestick' 7. Across the placenta or during childbirth 8. From mother to baby during breastfeeding It can remain unactive in the body for many years. Once the virus becomes active it attacks and destroys T helper cells in the immune system, effectively rendering the immune system useless Malaria parasite avoids producing an immune response • infects red blood cells or lives/reproduces inside red blood cells; • and in liver cells; • antigens (on surface) not exposed to/hidden from immune system/eq.; • different stages have different antigenic groups; • keeps changing its antigenic groups; No vaccine for malaria • different, strains / species / types (of Plasmodium); • different antigens; • due to, mutation / variation; • more than one stage in the life cycle (within human); • different stages have different antigens; • so will need, a different vaccine / components of vaccine, for each, strain / stage; • (parasite) concealed / hidden, in cells; • (parasite) only, exposed / in circulation, for short time Disrupt malaria cycle Reduce mosquito numbers: • Oil on surface of ponds • Spray bacteria to kill mosquito larvae • Pesticide spray • Draining ponds Avoid being bitten by mosquitoes • Wear insect repellent • Sleep with mosquitoes nets • Long sleeved clothes • Nets soaked in insecticide Use drugs to prevent infection • Use malaria vaccine 1. (mosquito), is vector; 2. Plasmodium/ parasite, present in (mosquito), saliva / salivary gland ; 3. idea that infected mosquito, feeds on / bites, human ; 4. Plasmodium/ parasite, passes (from saliva) to blood ; Tuberculosis The bacteria are contained in the tiny droplets of liquids which are released when an infected person coughs, sneezes or talks. But it takes close contact with an infected person over a long period of time to contract the disease. There are a number of conditions which make contraction and spread more likely: 1. Overcrowding- many people eating and sleeping together in one house 2. Poor ventilation 3. Poor health- particularly if a person has HIV/AIDS 4. Poor diet 5. Homelessness Living or working with people who are migrated from areas where TB is more common TB can also be contracted from the milk or meat of cattle. • not vaccinated against TB ; • weakened immune system ; • (lifestyle) e.g. poor diet / lack of protein / malnourished / smoking / alcoholism; • homelessness • poor ventilation (of housing) / AW ; • overcrowding ; • close contact with people from / visiting, area where TB is common ; • close / prolonged, contact with individual(s) with TB ; • consumption of milk or beef, from infected cattle / in developing countries ;

Discuss the global impact of malaria, AIDS/HIV and TB

Malaria Kills about 3 million people annually Affects about 300 million people Currently limited to areas where the Anopheles mosquito can survive, which is currently the tropical regions. But, with global warming, the Anopheles mosquito may be able to survive further north, even into parts of Europe. HIV/AIDS Spreading into pandemic proportions all over the world Approximately 45 million people living with HIV/AIDS at the end of 2005 More than half of these are in Sub-Saharan Africa About 5 million people infected each year By the end of 2005, nearly 30 million people had died from HIV/AIDS related illnesses It is thought that the number of people living with HIV/AIDS in China will soon exceed the number in any other country HIV/AIDS difficult to prevent because... 1. no cure; 2. no vaccine; 3. high mutation rate / antigenic, shift / drift / change; 4. cannot be treated with antibiotics; 5. symptomless carriers / long incubation period; 6. HIV is transmitted by, unprotected sexual contact / unscreened blood products / across placenta / in breast feeding / blood to blood contact / mixing of blood / reusing needles; 7. people reluctant to be tested for HIV; Higher rate increase in LEDC because... 8. poverty; 9. less education about, means of transmission / disease; 10. sexual attitudes / promiscuity / more partners / ref to sex industry; 11. lower availability of condoms; 12. religious / cultural, reasons; 13. denial / superstitious beliefs; 14. fewer, medical personnel / clinics / facilities / hospitals / (effective) drugs, 15. (to treat infected people); 16. less, screening of blood products / testing of people; 17. ref to government financial constraints; 18. (enforced) migration / refugee camps; 19. more infected mothers breast feed; 20. more cases of rape; 21. more intravenous drug abuse; 22. more use of, shared / unsterilised, needles; 23. AVP; e.g.lack of contact tracing 24. AVP;HIV inside cell so hidden from immune system /antigens concealed Tuberculosis Approximately 1% of the population is infected every year, and 10-15% of those will go on to develop the disease In 2005 there were 8.8 million new cases of Tuberculosis and 1.6 million people died. Up to 30% of the world's population may be infected with TB Why we research • to find out where rates, are highest / people are most at risk; • to keep track of infection rates over time/ AW; • to see where disease is likely to spread / where epidemic most likely; • to help research (into how it is spread / into effectiveness of drugs); • to allow organisations to provide, aid / health care, where it is needed most; • to allow organisations to provide education (about disease) where it is needed most • identify location where disease is spreading or predict, where / when, epidemic may arise; • find a way to prevent spread / isolate / quarantine; • ref to targeting vaccination; • give (individuals) advice on, lifestyle / diet / other named risk factor; • qualified ref to targeting funding; • ensure sufficient, medicines / antibiotics / vaccines / facilities, are • available; ensure enough medical personnel are available; • qualified ref to education of population; • prioritising diseases; • target screening; • assess effectiveness of treatment programme

Explain how consumption of an unbalanced diet can lead to malnutrition, with reference to obesity

Malnutrition is caused by an unbalances diet. Obesity is called by consuming too much energy and the excess energy is deposited as fat in the adipose tissues. Obesity is the condition in which excess fat deposition impairs health and it usually defined when a person has a BMI (BMI = Mass (kg) / (height (m) 2)) of 30 or over. This indicated a body weight of 20% or more above the weight recommended for the height.

Outline the mode of action of antibodies, with reference to the neutralisation and agglutination of pathogens

N1 neutralisation ; N2 antibodies , cover binding sites on pathogen / bind to toxins ; N3 prevent , binding / entry , to (host) cell A1 agglutination ; A2 clump / bind together , (many) pathogens ; A3 (clump) too large to enter host cell / increase likelihood of being consumed by (named) phagocyte ;

Compare and contrast active, passive, natural and artificial immunity

NATURAL Active Immunity provided by antibodies made in the immune system as a result of infection Advantage: Long term immunity Disadvantage: Immune response takes a long time, symptoms develop, disease may be fatal Passive Antibodies provided via the placenta or via breast milk. It makes the baby immune to diseases that the mother is immune to. Advantage: Immediate protection against disease to which the mother has active immunity Disadvantage: Short term, no memory cells produced ARTIFICIAL Active Immunity provided by antibodies made in the immune system as a result of vaccination. Advantage: Long term immunity without suffering from the disease Disadvantage: Immune response takes a long time Passive Immunity provided by injection of antibodies made by another individual Advantage: Immediate protection against a specific disease Disadvantage: Short term, no memory cells produced Passive The person does not produce an immune response No memory cells are produced Active The person does produce an immune response Memory cells produced

Explain the relationship between classification and phylogeny

Natural Classification • Grouping species according to; o Appearance o Anatomy o Physiology o Biochemistry o Genetics • Organisms of the same species can o Breed together and produce offspring o The offspring must be fertile • Organisms of the same species can show variation Phylogeny • The study of how closely different species are related to each other • Reflects evolutionary relationships between species. • Generally presented in phylogentic (or evolutionary) trees. • Used to inform natural classification o it is based on the evolutionary relationships between organisms (phylogeny) o it classifies species into groups using shared features derived from their ancestors o it arranges the groups into a hierarchy

Why TB is not irradicated

New strains have developed due to mutation New vaccine must be created/ no vaccine available / drug resistance LED have not be educated on how to prevent the spread of the disease LED cannot afford vaccine/ poor Overcrowding population can allow TB to spread easily Untreated milk

Describe the effects of nicotine and carbon monoxide in tobacco smoke on the cardiovascular system with reference to the course of events that lead to atherosclerosis, coronary heart disease and stroke

Nicotine: • addictive; • adrenaline released; • increases heart rate; • reduced circulation to extremities / vasoconstriction; R contract • A narrow lumen • sticky platelets; risk of blood clots • cause blood clotting / thrombosis; Carbon Monoxide • binds to haemoglobin / forms carboxyhaemoglobin; • irreversibly / permanently; A greater affinity than for oxygen • less effective oxygenation of haemoglobin; R oxidation • shortage of breath; • damages lining of arteries; Atherosclerosis Carbon monoxide can damage the endothelium of the arteries. The damage is repaired by phagocytes. This encourages the growth of smooth muscle and the deposition of fatty substances. The deposits include cholesterol from low-density lipoproteins. These deposits (atheromas) may also include fibres, dead blood cells and platelets. The atheroma eventually forms a plaque which sticks out into the lumen of the artery. This leaves the artery wall rougher and less flexible. It also reduces the lumen of the artery, reducing blood flow. Coronary Heart Disease • The coronary arteries carry blood to the heart muscles. They carry blood at high pressure which makes them prone to damage and atherosclerosis. • When the lumen of a coronary artery is narrowed by plaques, there is less blood flow to the heart muscle, so they receive less oxygen for respiration. o Angina- A severe pain in the chest which may extend down the left arm or up the neck o Heart attack or myocardial infarction- the death of part of the heart muscle, usually caused by a clot in the coronary artery blocking the flow of blood to the heart muscle o Heart failure- when the heart cannot sustain its pumping action; this can be due to the blockage of a major coronary artery, but there are other types and causes. Stroke • Death of part of the blood tissue due to the loss of blood flow to that part of the brain. Two possible causes: 1. A blood clot floating around in the blood blocks a small artery leading to part of the brain 2. An artery leading to the brain bursts • Sudden numbness/weakness in the face, arm or leg on one side of the body • Sudden confusion or trouble speaking, seeing, loss of balance or coordination.

Define and discuss the meanings of the terms parasite

PARASITE: is a organism that lives in or on another living thing that causes harm to the host lives, on / in / in contact with, and harms host ; takes nutrition from / feeds on (host) ; warmth ; protection / safe place / AW ; allows transmission / spread, to a new host / AW ;

Define and discuss the meanings of the terms pathogen

PATHOGEN: is an organism that causes a disease

Discuss why the evolution of pesticide resistance in insects and drug resistance in microorganisms has implications for humans

Pesticide resistance in Insects • The pesticide applies a very strong selective pressure • Any susceptible insects will die • If any insects have resistance they survive • The survivors are the only individuals that can breed • All offspring have resistance to the pesticide • Resistance spreads through the population quickly Resistance to insecticides has developed in different ways: 1. Resistance can come from the insects being able to break down the pesticide by having enzymes which work on the chemical 2. The protein target receptor that the pesticide binds to may change and the pesticide can no longer bind to it. Problems with pesticide resistance • Insects can destroy crops E.g. Locusts • Insects can carry diseases E.g. Mosquitos and Malaria • Bioaccumulation of the pesticide up the food web can occur Drug resistance in microorganisms • Antibiotics are a strong selective pressure on microorganisms • Any susceptible microorganisms will die • If any microorganisms have resistance they survive • The survivors are the only individuals that can breed • All offspring have resistance to the antibiotic • Resistance spreads through the population quickly How to reduce antibiotic resistance • Always complete the course of antibiotics • Only take antibiotics when necessary (Not for viral infections) Problems with antibiotic resistance • MRSA has developed resistance to an ever increasing range of stronger and stronger antibiotics.

Explain that humans depend on plants for food as they are the basis of all food chains.

Plants can carry out photosynthesis to convert light energy to chemical energy. They also absorb plants from the soil and manufacture a range of other biological molecules. Herbivores make use of these biological molecules when they eat and digest food. Humans eat both plants and herbivores, gaining our nutrition both directly and indirectly.

Outline the characteristic features of the following five kingdoms: Prokaryotae (Monera), Protoctista, Fungi, Plantae, Animalia

Prokaryotae (Monera) 1. No nucleus 2. Loop of naked DNA a. No Chromosomes 3. No membrane-bound organelles 4. Smaller ribosomes 5. Carry out respiration in mesosomes 6. Smaller cells 7. May be free living or parasitic Protoctista 1. Eukaryotes 2. Mostly single celled 3. Show a wide variety of forms 4. Show various plant-like or animal-like features 5. Mostly free living Have autotrophic or heterotrophic nutrition Fungi 1. Eukaryotes 2. Have mycelium which consists of hyphae 3. Walls made of chitin Cytoplasm is multinucleate 4. Mostly free living and saprophytic Plantae 1. Eukaryotes 2. Multicellular 3. Cells surrounded by a cellulose cell wall 4. Produce multicellular embryos from fertilised eggs 5. Autotrophic nutrition Animalia 1. Eukaryotes 2. Multicellular 3. Heterotrophic nutrition 4. Have fertilised eggs that develop into balls of cells called blastula 5. Usually able to move around

Explain, with the aid of diagrams, the term quaternary structure, with reference to the structure of haemoglobin

Protein structure where a protein consists of more than ONE polypeptide chain. Haemoglobin has a quaternary structure as it is made up on four polypeptide chains.

Outline the roles of DNA and RNA in living organisms (the concept of protein synthesis must be considered in outline only)

Protein synthesis The required gene can be exposed by splitting the hydrogen bonds that hold the double helix together in that region RNA nucleotides form a complementary strand (mRNA). This is a copy of the DNA coding strand The mRNA peels away from the DNA and leaves the nucleus from the nuclear pore The mRNA attaches to a ribosome Then tRNA molecules bring amino acids to the ribosome in the correct order, according to the base sequence on the mRNA The amino acids are joined together by peptide bonds to give a protein with a specific tertiary structure mRNA is short idea that only copies one, gene / section / part / AW, (of DNA) ; idea that DNA comprises many, genes / alleles DNA unable to leave nucleus 3 (m)RNA , copies / is a copy of , gene(s) / part of DNA ; 4 (RNA) passes , out of nucleus / through nuclear pore / into cytoplasm ; 5 to / at , ribosome / RER ; 6 ribosome made of (r)RNA ; 7 (RNA needed for) protein synthesis / formation of polypeptides / AW ; 8 amino acids brought by (t)RNA ;

Discuss the importance of international co-operation in species conservation with reference the Rio Convention on Biodiversity

Rio Convention Aims: 1. Conserve biological diversity 2. Use components sustainably 3. Have appropriate shared access to genetic resources 4. Have appropriate sharing and transfer of scientific knowledge and technologies 5. Have fair and equitable sharing of the benefits arising out of the use of genetic resources Zoological and Botanical gardens • Swap genetic material to increase genetic diversity Rio Convention2 max • sustainable use of ,organisms / habitats / ecosystems ; • share genetic resources ;share access to ,scientific knowledge / technology ; • idea of promoting (named) ex situ conservation method(s) ; • idea of raising profile of (biodiversity) with , governments / publicbodies / general public; • idea of international cooperation (on biodiversity issues)

Describe the effects of smoking on the mammalian gas exchange system, with reference to the symptoms of chronic bronchitis, emphysema (chronic obstructive pulmonary disease) and lung cancer

SHORT TERM OF TAR 1. Tar 2. destroy / paralyse, cilia; 3. mucus not removed; 4. over- active goblet cells / extra mucus produced; 5. (accumulation of mucus) leads to, infections / bronchitis; a. e.g.'tar destroys cilia' = 2 LONG TERM OF TAR 6. neutrophils / phagocytes / macrophages / monocytes (invade); 7. secrete, enzyme / elastase; 8. elastin / elastic fibres, digested / destroyed; 9. low(er) level of, elastase inhibitor / α antitrypsinase; 10. alveoli fail to recoil; 11. constriction of (terminal) bronchioles; 12. (so) coughing / forced expiration, causes alveoli to burst; 13. reduced surface area • coats the (internal) surfaces of breathing system; A lungs • reducing efficiency of exchange; • irritation of mucous membranes; • goblet cells stimulated/over secretion of mucus; • inactivation of, cilia / ciliated epithelium; A destroys / damages R kills • mucus not moved; • coughing; • carcinogenic / cancer-causing / causes mutations; • causes emphysema/ described; R ref to elastin damage alone • e.g. ref to more infections / increased risk of chronic bronchitis CHRONIC BRONCHITIS • Inflammation of the lining of the airways, damage to the cilia and overproduction of mucus Symptoms • Irritation of the lungs • Coughing up mucus that it often filled with bacteria and white blood cells EMPHYSEMA Symptoms • shortness of breath / shallow breathing / • strained breathing / hard to breathe out / wheezing; • barrel chest; • fatigue / extreme tiredness / cannot exert themselves; • pulmonary hypertension / high blood pressure to lungs; • enlargement of right side of heart; • heart failure / congestive cardiac failure / fluid build up in lungs; • cyanosis / skin with blue tinge; LUNG CANCER • Continual coughing • Shortness of breath • Pain in the chest • Blood coughed up in the sputum

Describe, with the aid of diagrams, the mechanism of action of enzyme molecules, with reference to specificity, active site, lock and key hypothesis, induced-fit hypothesis, enzyme-substrate complex, enzyme-product complex and lowering of activation energy

SPECIFICITY: The active site of an enzyme is a specific shape, depending on the reaction that it catalyses, meaning that other molecules won't fit into the active site ACTIVE SITE: The area on an enzyme to which the substrate binds lock and key hypothesis, The theory of enzyme action in which the enzyme active site is complementary to the substrate molecule, like a lock and key INDUCED FIT HYPOTHESIS: The theory of enzyme action in which the enzyme molecule changes shape to fit the substrate molecule more closely as it binds to it ENZYME SUBSTRATE COMPLEX: The intermediary formed when a substrate molecule binds to an enzyme molecule ENZYME SUBSTRATE PRODUCT: The intermediate structure in which product molecules are bound to an enzyme molecule LOWERING OF ACTIVATION ENERGY: Enzymes reduce the activation enthalpy so the reaction can proceed at a much lower temperature

Discuss the role of botanic gardens in the ex situ conservation of rare plant species or plant species extinct in the wild, with reference to seed banks

Seed banks A seed bank is a collection of seed samples. This is extremely useful because: • The seeds are stored in large number with a huge variety, maintaining a large gene pool and significant genetic diversity • This allows for the reintroduction and repopulation of the plant species if they became extinct • They may be used for breeding crop plants • They could be used for research into new medicines or other forms of scientific research Storage of seeds Scientists must work to maintain the viability (ability of the seeds to germinate) and genetic variability of the seeds. • Viability -Suitable storage conditions i.e. cold, dry conditions are used to store the seeds for long periods of time -New seeds are continually being collected for storage -Germination tests are frequently run - this usually consists of planting the seeds in nutrient agar to check that they are still able to germinate • Genetic variability -Vast number of seeds are collected -Seeds are collected from a variety of habitats -This maintains a mixture of genotypes in the seeds collected [plants] Advantage -Collecting seeds has little disturbance to plants or ecosystem -Stored and germinated under specific protected environment -Seeds are easily stored -Plants can be reproduced asexually through cuttings and tissue culture -Huge seed numbers for research Disadvantage -There will be some disturbance to plants or ecosystem -Shelf life of seeds -Asexual cloning can lead to genetic uniformity -Seeds can deteriorate over time when stored -Collected seeds may not represent all genetic variation • most plants produce an excess ; • (so) can be collected (from wild) without damaging (wild) , plants / organisms / population / habitat ; • take up little space; ora • able to store, large numbers / more species ; ora • easy / cheaper, to transport / AW ; ora • idea of remaining viable for long periods ; ora • less susceptible to, disease / pests / environmental change can be collected with minimal damage to (wild) , population / habitat / ecosystem ; take up lit tle space / larger numbers can be stored ; ora can store great ( er ) , genetic / allelic , diversity ; ora low ( er ) maintenance / manpower costs / AW ; ora easy / cheaper, to transport / AW ; ora idea of remaining viable for long periods ; ora le ss , susceptible / vulnerable , to, disease / pests / environmental change ; ora idea that prevents fertilisation by undesired pollen;

Describe the primary defences against pathogens and parasites (including skin and mucus membranes) and outline their importance.

Skin • Consists of many layers of skin cells (Keratinocytes) • New cells made by mitosis at the base of the epidermis and migrate towards the outer surface as they mature. • As they mature they undergo Keratinisation and die. This is where the cytoplasm is replaced by Keratin. (takes 30 days) • The keratinised layer of dead cells is a very effective barrier Mucous membranes Oxygen and nutrients must enter our blood, so the body is exposed to infect as they could be harbouring microorganisms. So, the airways, lungs and digestive systems are protected by mucous membranes. The epithelial layer contains mucus secreting-goblet cells. In the airways, the mucus lines the passages and traps any pathogens that may be in the air. The epithelium also has ciliated cells. The cilia move in a coordinated fashion to waft the layer of mucus up to the top of the trachea where it can enter the oesophagus. It is swallowed and passes into the digestive system. Most pathogens in the digestive system are killed by the acid in the stomach (pH 2)

Describe how to measure species richness and species evenness in a habitat

Species Richness -Qualitative • NUMBER OF SPECIES PRESENT IN A HABITAT • The more species the greater the richness • It does not take account of the number of individuals in each species • Estimated by making observations within the habitat and record all the different species you see. Species Evenness- Quantitative • A MEASURE OF THE RELATIVE NUMBERS OF ABUNDANCE OF INDIVIDUALS IN EACH SPECIES • A habitat where there is a more even distribution of individuals in each species is more likely to be more diverse than one in which individuals of one species greatly outnumber all the others • Estimated by counting individuals or measuring percentage cover The higher the species richness and species evenness the higher the biodiversity Surveying plant frequency - count the number of plants of each species per unit area or measure the percentage cover of each species Counting the number of individuals present (larger animals) Mark-and-recapture of small animals Total population= (number captured ×number recaptured)/(number marked from recaptured sample) Soil sampling/river mud sampling Surveying plant frequency - count the number of plants of each species per unit area or measure the percentage cover of each species Counting the number of individuals present (larger animals) Mark-and-recapture of small animals Total population= (number captured ×number recaptured)/(number marked from recaptured sample) Soil sampling/river mud sampling • (measures), abundance / numbers, of individuals in each species ; • species evenness is more quantitative than species richness ; ora • high(er) species evennessindicates high(er) biodiversity ;ora • low species evenness indicates, DOMINANCE by / high abundance of, one / few, species ;ora • used to calculate (Simpson's) Index of Diversity ;

Describe how to carry out chemical tests to identify the presence of the following molecules: protein (biuret test), reducing and non-reducing sugars (Benedict's test), starch (iodine solution) and lipids (emulsion test)

Starch •iodine solution (potassium iodide) is added to a sample •Present--> turns yellow to blue- black Reducing sugars •Add Benedict's solution (alkaline copper sulphate) •Heat to 80˚C •Solution turns blue to orange- red precipitate Non- reducing sugar 1. First you make sure there are no reducing sugars in the sample 2. Boil the sample with HCl (to hydrolyse) 3. This hydrolyses any sucrose present, splitting sucrose molecules to give glucose and fructose monosaccharides (breaking glycosidic bonds by hydrolysis) 4. Cool the solution and add sodium hydrogencarbonate/ sodium carbonate to neutralise 5. Carry out the reducing sugar test again 6. If sucrose is present in the original sample, the test will now give a positive result because the monosaccharides glucose and fructose are present Proteins •Biuret reagent is a pale blue colour, contains sodium hydroxide and copper sulphate •Chemicals react with peptide bonds found in proteins •Colour change pale blue to lilac Lipids •Use ethanol emulsion test oMix the sample with ethanol (an alcohol) this dissolves any lipid present (lipids are soluble in alcoholds) oThen pour the liquid into water contained in another clean test tube oIf lipid is present = cloudy white emulsion will form near the top of the water CANT TEST ON MILK BECAUSE MILK IS CLOUDY SO POSITIVE TEST WOULDNT APPEAR

Explain how the structures of glucose, starch (amylose), glycogen and cellulose molecules relate to their functions in living organisms

Starch (plants) •Starch =Long, straight chained amylose molecules+ Branched amylopectin •Stored in chloroplast and in membrane bound starch grains •Starch can be broken down into glucose molecules and respired •1,4 glycosidic bond is longer than glycogen •Less branches •Less compact than glycogen Glycogen •Made up of α Glucose •Forms glycogen granules in animal cells •can be broken down into glucose molecules and respired •1,4 glycosidic bond is shorter than starch •More branches •More compact than starch Amylopectin •Shorter main branch of α 1,4 glycosidic bonds •Main branches are α 1,6 glycosidic bonds •Side branches allow enzyme to break down the molecules to get at the glycosidic bonds easily --> glucose released quickly--> more SA

Describe, with the aid of diagrams, the formation and breakage of peptide bonds in the synthesis and hydrolysis of dipeptides and polypeptides

Synthesis The -OH from one amino acid and the -H from the -COOH from the other are removed to make water, and the C and the N join together via a peptide bond (CONH) Hydrolysis A water molecule is used to break the peptide bond. The -H joins back to the N, and the - OH back to the C

Explain, with the aid of diagrams, the term secondary structure with reference to hydrogen bonding

The coiling or folding of parts of a protein molecule due to the formation of hydrogen bonds formed at the protein is synthesised. The main forms are the α-helix and the β-pleated sheet.

Other primary defenses

The eyes are protected by antibodies in the tear fluid contains lysosomes The wax in the ear canal traps pathogens The conditions around the vagina are relatively acidic skin ; idea of: physical barrier to prevent entry of microorganisms ; mucous membrane (s) / goblet cells ; (produce) mucus to trap, pathogens / parasite ; OR mucus ; traps pathogens ; cilia / ciliated epithelium ; remove, pathogen / parasite, laden / AW, mucus ; blood clotting ; prevents, pathogens / parasite, entering bloodstream ; ear wax / nasal hairs ; traps, pathogens / parasite ; lysozyme / tears / nasal secretions / saliva ; kills bacteria / contains antibacterial agent ; gastric juice / stomach acid ; kills, pathogens / parasite ;

Explain, with the aid of diagrams, the term tertiary structure

The overall three-dimensional structure of a protein molecule. It is the result of interactions between parts of the protein molecule such as hydrogen bonding, formation of disulfide bridges and hydrophobic interactions 1. some R groups, attract / repel; 2. disulfide, bridges / bond; 3. between, cysteine / SH / S (atoms); 4. hydrogen / H, bonds; 5. ionic bonds between, oppositely charged / + and -, R groups; 6. hydrophilic R groups, on outside of molecule / in contact with water (molecules); 7. hydrophobic R groups, on inside of molecule / shielded from water (molecules)

Define the term habitat

The place where an organism lives

Define the term variation

The presence of variety- differences between individuals

Explain, with the aid of diagrams, the term primary structure

The sequence of amino acids found in a protein molecule

Define the term taxonomy

The study of classification principals

Define the term phylogeny

The study of evolutionary relationships with organisms

Define the term biodiversity

The variety of life, range of habitats, and a number of different species

Describe, with the aid of diagrams and photographs, the structure and mode of action of phagocytes

There are 2 main types: 1. Neutrophils: manufactured in the bone marrow. They travel in the blood and are often squeeze out of the blood into the TF. They are often short lived, but they will be released in large numbers as a result of an infection 2. Macrophages (Matured monocytes): manufactured in the bone marrow. They travel in the blood as MONOCYTES. They tend to settle in the lymph node--> they develop into macrophages PHAGOCYTES ARE SECONDARY DEFENSE AS THEY CAN BREAK DOWN ANY CELLS AND CAN PASS FROM THE BLOOD TO THE TISSUE FLUID lobed / narrow , nucleus ; (cells) can change shape ; can squeeze / move / fit / AW , between cells / through pores , in (walls of) capillaries ; histamine makes , capillary walls / endothelium , leaky Pathogen attachs to phagocyte by antibody and surface receptor Pathogen engulfed by infolding of phagocyte membrane Lysosomes release lysins into the phagosome (a vacuole with the pathogen trapped inside) Harmless products of digestion are absorbed pathogen) engulfed / enveloped / surrounded by cytoplasm (from phagocyte) ; endocytosis / phagocytosis ; (formation of) phagosome / phagocytic vacuole / phagocytic vesicle ; (phago) lysosomes ; (lysosomes / phagosome) move towards / fuse with (each other) ; (named) enzyme(s) / lysins / hydrogen peroxide / free radicals (in lysosomes) ; (pathogen) digested / broken down / hydrolysed ; (to) amino acid / sugar / glucose / fatty acid / glycerol ; (break down products) absorbed / AW (into cytoplasm) or unwanted products removed (by exocytosis) ; cytoskeleton involved in (endocytosis / movement of vesicles) stage A phagocyte, attaches / binds / AW, to bacterium / pathogen ; receptor (on phagocyte), attaches to / binds to / recognises / AW, antigen (on bacterium) ; stage B bacterium, engulfed / enters by endocytosis / enters by phagocytosis / AW ; (formation of) phagosome / phagocytic vacuole ; stage C lysosomes , fuse with / join with / move towards (phagosome) ; release / secrete, enzymes / lysins / named enzyme / hydrogen peroxide / free radicals (into phagosome) ; stage C/D bacterium, digested / broken down / hydrolysed ; (to) amino acid / sugar / glucose / fatty acid / glycerol ; stage D absorbed / AW, into, cytoplasm / cytosol ; by, (facilitated / simple) diffusion / active transport

Describe, with the aid of diagrams, how hydrogen bonding between complementary base pairs (A to T, G to C) on two antiparallel DNA polynucleotides leads to the formation of a DNA molecule, and how the twisting of DNA produces its 'double-helix' shape

There are two types of nucleotide bases- pyramidines and purines. They always pair up together, with the purine Adenine always with the pyramidine Thymine, and the purine Guanine always with the pyramidine Cytosine. There are two hydrogen bonds between A and T, and three between G and C. The strands are antiparallel because they run in opposite directions- the sugars are pointing in opposite directions. The antiparallel chains twist like a rope ladder to form the final structure- a double helix.

Compare, with the aid of diagrams, the structure of a triglyceride and a phospholipid

Triglyceride 1. Glycerol plus three fatty acids 2. 3 Ester bond 3. Insoluble Phospholipid 1. Glycerol plus two fatty acids and a phosphate group 2. OH group is covalently bonded to phosphate group 3. 2 Ester bond 4. Phosphate head= hydrophilic Hydrocarbon chain fatty acid tails are hydrophobic 5. Majority is insoluble but water soluble head gives phospholipids their characteristics in terms of the capacity to form membranes 6. Fatty acid may be saturated or unsaturated 7. Organism can control the fluidity of the membrane e.g. colder climates have an increase number of unsaturated fatty acids in their phospholipid molecules. This ensure that membranes remain fluid, despite low temperature

Explain how the structures of triglyceride, phospholipid and cholesterol molecules relate to their functions in living organisms

Triglyceride Compact energy store Insoluble in water Does not affect cell water potential Phospholipid Part hydrophilic, part hydrophobic, so ideal basis for cell surface membranes Cholesterol Small, thin molecules that can fit into the lipid bilayer giving strength and stability thermal) insulation ; energy, store / source / release ; protection ; membranes / phospholipid bilayer / control entry and exit into cells ; (steroid) hormones / named steroid hormone ; buoyancy ; waterproofing ; source of water (from respiration) ; (electrical insulation) in myelin / around neurones / around axons / around dendrons ; aid, absorption / storage / production, of, fat soluble / A / D / E / K, vitamins ;

Describe and explain the effects of temperature on enzyme activity

Up to a certain point, increasing temperature will increase the rate of reaction, as there will be more collisions between enzymes and the substrate, and more of these collisions will have the required activation enthalpy for the reaction to proceed. But heat also makes the molecules vibrate. This puts strain on the inter-molecular bonds, and some of the weaker bonds (hydrogen bond and ionic bonds) may break. In enzymes there are large numbers of these bonds holding the tertiary structure, and especially the active site, in place. As the heat increases, more and more of these bonds are broken The tertiary structure disintegrates further and further The rate of reaction decreases If enough of these bonds are broken, the entire tertiary structure will unravel and the enzyme will stop working This is not reversible and is known as denaturation At optimum temp- max 3 marks 1. molecules in culture have kinetic energy; 2. (frequent) collisions between enzyme and substrate molecules; 3. more enzyme-substrate complexes formed; 4. max rate of reaction / protein production achieved; At higher temp - max 5 marks 5. (at higher temperature) molecules have more kinetic energy /collisions occur more frequently and with more energy; 6. molecules vibrate and, bonds/ hydrogen bonds, broken; 7. tertiary structure / 3D shape, of enzymes altered; 8. active site loses, precise / complementary, shape; 9. enzymes are denatured; 10. substate molecule no longer fits active site; 11. (may be) irreversible so reaction/ protein production stops; A fungus destroyed

Describe how the effects of enzyme concentration on enzyme activity can be investigated experimentally

Use the reaction as before, but keeping the temperature constant, and instead having a different number of potato discs in each test tube

Explain how vaccination can control disease

Vaccination provides immunity to specific diseases. A person who has been vaccinated has artificial immunity. This is created by the deliberate exposure to antigenic material that has been rendered harmless. The immune system treats the antigenic material as if it was a real disease. As a result, the immune system manufactures antibodies and memory cells. The memory cells provide the longterm immunity. Source of antigenic material • Whole live microorgaisms (live vaccine) with similar but less harmful antigens (e.g. smallpox) • Attenuated (made harmless) form of the pathogen (e.g. measles, TB) 1. Living but modified 2. Reduced reproduction rate 3. Given heat/ chemical treatment 4. Ad: resembles a real infection/ provokes a better immune response and immunity is longer Herd vaccination: vaccinates most people, stops infection spreading Ring vaccination vaccinate all victim to contain the spread (ring)

Discuss the fact that variation occurs within, as well as between species

Variation occurs within a species- eye colour, hair colour, height- as well as between species, which are obvious differences; birds fly whereas dogs do not. Variation can be interspecific (differences between species) or intraspecific (differences within a species from one individual to another).

Describe how hydrogen bonding occurs between water molecules

Water is a polar molecule. This is because the oxygen atom pulls the shared electrons towards it, meaning that water is slightly negatively charged at the oxygen and positively charged at the hydrogen ends, so they can form hydrogen bonds with each other. This are continuing breaking and reforming, so the molecules can move around

Explain the effects of competitive and non-competitive inhibitors on the rate of enzyme-controlled reactions, with reference to both reversible and non-reversible inhibitors

competitive inhibitor ~ (3marks) 10. inhibitor has similar shape to substrate; 11. can, fit / occupy, active site; 12. for short time / temporary / reversible; 13. prevents / blocks, substrate from entering active site; 14. rate determined by relative concentrations; 15. little inhibition / rate little reduced, if substrate conc. > inhibitor conc.; 16. ref to chance of, substrate / inhibitor, entering active site; 17. effects can be reversed by increasing substrate conc. Non competitive inhibitor Do not compete for the active site binds to allosteric site Changes shape of active site so ESC cannot form, decreasing rate of reaction This is irreversible, no effect increasing the substrate concentration

Define the term classification

grouping organisms based on their similarities and differenences placing, living things / organisms / named organisms, into, groups / categories / taxa / named taxonomic groups ; based on / AW, similarity / difference

Describe, with the aid of diagrams, the structure of glycogen

has many 1-4 glycosidic bonds, but there are 9% 1-6 branches

Why vaccines aren't always effective

immune system may be defective / underdeveloped ; malnutrition / insufficient protein in diet ; more than one strain / antigenic, variation / drift / shift / pathogen may change antigens regularly ; antigenic concealment / pathogen lives inside host cells / pathogen uses host antigens /pathogen lives in gut ; pathogen eukaryotic / has many antigens ; AVP ; e.g. pathogen or toxin build up being too rapid for response e.g. rabies, lassa fever passive immunity from breast milk may destroy antigens before immunity developed using immunosuppressant

Use Simpson's Index of Diversity (D) to calculate the biodiversity of a habitat, using the formula D = 1-(Σ(n/N)2)

n is the number of individuals of a particular species N is the total number of individuals for all species

Describe and explain the effects of pH on enzyme activity

pH Low pH = lots of H+ ions H+ ions have a positive charge Either extreme of H+ ion concentration can interfere with the hydrogen and ionic bonds holding the tertiary structure together. The pH affects the charge of the amino acids at the active site, so the properties of the active site change and the substrate can no longer bind At high pH values, a -COOH group will dissociate to become a charged -COO- group (so) charges in active site do not change ; ora (so) hydrogen / ionic , bonds unaffected ; ora (so) tertiary structure / 3D shape / active site , unaltered ; ora (so) enzyme / tertiary structure , does not denatur e ; ora (so) subst rate , fits / is complementary shape to , active site ; ora so the results are valid / as the rate (of reaction) will vary if pH varies / so that only one (independent) variable is changed

State that deoxyribonucleic acid (DNA) is a polynucleotide, usually double stranded, made up of nucleotides containing the bases adenine (A), thymine (T), cytosine (C) and guanine (G)

part of nucleotide ; bonded / joined / attached , to (named) base and phosphate ; phosphate (joined) to C5 (and C3) / base (joined) to C1 ; (deoxyribose is part of) backbone (of DNA) ; idea of linking with (second) phosphate on adjacent nucleotide ; nucleotide is , monomer / repeating unit , of DNA / polynucleotide

Outline how salting, adding sugar, pickling, freezing, heat treatment and irradiation can be used to prevent food spoilage by microorganisms.

salting ; lack of water due to, osmosis / low water potential (outside cell) ; sugar lack of water due to, osmosis / low water potential (outside cell) ; (air / freeze) drying ; idea that enzymes cannot mobilise / intracellular transport impaired / reactions have no medium in which to occur / (microbes) cannot move ; pickling / (use of) vinegar (low pH) denatures / changes tertiary structure of / changes 3D shape of, enzymes / proteins OR substrate no longer fits active site / active site shape changes /prevents ESC ; heat treatment / cooking denatures / changes tertiary structure of / changes 3D shape of, enzymes / proteins OR substrate no longer fits active site / active site shape changes / prevents ESC ; irradiation / UV / gamma rays / X-rays / ionising radiation destroys / damages / changes / mutates, DNA / genes / genetic material ; smoking (so exposed to) antibacterial / named antibacterial, chemical(s) ; vacuum packing / canning / bottling microorganisms cannot respire aerobic ally

effect of smoking on lung cancer

tar / (cigarette) smoke , contains carcinogen s / is carcinogen ic ; benzopyrene / formaldehyde / other e.g. ; enters , lung / epithelial , cells ; idea that destroyed cilia prevent removal of , carcinogens / tar , which then have greater contact time with epithelial cells ; enters nucleus / in contact with DNA ; causes mutat ion ; proto-oncogenes to oncogenes ; uncontrollable , cell division / mitosis ; formation of , tumour / mass of cells ; no , programmed cell death / apoptosis

Explain the benefits for agriculture of maintaining the biodiversity of animal and plant species

• A decrease in biodiversity means a decrease in genetic diversity • Valuable resources • Wild plants have evolved over thousands of years. They have adapted to overcome the problems presented by the environment. They have overcome pests and diseases found in the area • Selective breeding can lead to new crop varieties that can cope with new conditions created by the climate change. • The range of potential medicines and vaccines that could be developed from species is unknown 1. source of food; 2. source of plant varieties for cross breeding / selection; 3. to breed in disease resistance / pest resistance; 4. to breed in other named characteristic; e.g. higher protein content / quicker growth 5. source of natural predators to pests

State that metabolic poisons may be enzyme inhibitors, and describe the action of one named poison

• Ethylene glycol is found in antifreeze which is used in car engines. • Ethylene glycol is itself not poisonous, but if taken in large quantities it can be broken down into Oxalic acid which is extremely poisonous and can lead to death. • Ethylene glycol is broken down by the enzyme alcohol dehydrogenase into Oxalic acid. • If someone is suspected of taking ethylene glycol then they are given large quantities of ethanol. • This leads to severe but less likely to be fatal -alcohol intoxication. • Ethanol acts as a competitive inhibitor to alcohol dehydrogenase. • This reduces the production of Oxalic acid and allows ethylene glycol to be excreted harmlessly.

Explain how biodiversity may be considered at different levels; habitat, species and genetic;

• Habitat: The range of habitats in which different species live. Diversity of all possible habitats or ecosystem • Species: The differences between species. Diversity of species in an area. Can be structural (i.e 2 different species) or functional diversity (i.e. similar species performing different roles) • Genetic: Genetic variation between individuals of a species. Diversity of genetic characteristics of a species. Variation within a species

Outline the binomial system of nomenclature and the use of scientific (Latin) names for species

• Latin names • Genus - noun, capitalised • Species - descriptive, lower case • Underlined in handwritten text Advantages: • The same name can be used all over the world in all languages, avoiding difficulties of translation • Name reflects closeness of relation to other species and may describe its characteristics • Avoids confusion with different common names for the same species or the same common name for different species • Allows easy identification of species e.g. in EIAs

Outline how selective breeding is used to produce domestic animals with high productivity

• Mutation in alleles • Organisms with these alleles reproduce • Pass the trait on to the offspring • Reproduce over many generations

Outline how selective breeding is used to produce crop plants with high yields, disease resistance and pest resistance

• Mutation in alleles • Organisms with these alleles reproduce • Pass the trait on to the offspring • Reproduce over many generations • artificial selection/ selective breeding; • cross / breed, Iranian / resistant, wheat with, high yield / UK, wheat; • method to prevent self, pollination / fertilisation; • select, best offspring / offspring with good yield and resistant; • (back) cross to high yield (UK) wheat / interbreed best offspring / interbreed offspring with both characteristics; • idea of breeding (and selecting) for many generations;

Discuss the responses of governments and other organisations to the threat of new strains of influenza each year

• Pathogenic organisms can form a new strain by mutation • New vaccine may have little/ no effect • In the UK there is an immunisation program to vaccinate all over 65s and those who are in 'at risk' groups. In 2006/7, 74% of over 65s were vaccine and 42% of people in the 'at risk' groups. The strains of flu used in the immunisation program changes every year. Research is undertaken to determine which of the strains of flu are most likely to spread that year

Outline the reasons for the conservation of animal and plant species, with reference to economic, ecological, ethical and aesthetic reasons

• maintains biodiversity • part of food chain /part of ecosystem / part of food web / • scavengers • have a right to existence / moral reason • specific religious reason • give pleasure / beautiful creatures • ecotourism • useful product / source of medicine / medical research • genetic resource • saves clearing up / remove carcasses • prevents disease • keeps, rat / dog, population down Ecological • prevents disruption of food, chains / webs; • maintenance of, ecosystems / habitats; • interdependence of species / AW; • 4+5credit two good examples;; e.g. dispersal of seeds, pollination Economic • importance of gene pool; • some species, may be of use in the future / not yet discovered; • for medicinal purposes; • example; • fishing / agricultural / silvicultural, purposes; • could be crossed with existing agricultural, species / strains; • to improve yield; • increase hardiness; • increase, disease / pest resistance; • tourism; Ethical • reduction in biodiversity is a result of human activity, so have a moral responsibility to try to put things right / AW; • for future generations; Difficult to find new drugs 1. Drug comes from organisms 2. Biodiversity is reducing 3. Habitats destroyed by deforestation 4. Habitats destruction e.g. global warming

Describe, with the aid of diagrams, the structure of antibodies

• variable region is antigen binding site; R receptors / 'sticky ends' /active site o antibodies have different shapes • (shape of) variable region specific to antigen / amino acid sequence (of variable region) gives, complementary / matching, shape; • hinge region allows flexibility in binding / AW; • constant region, for binding to receptors on cells / phagocytes / mast cells; • AVP; e.g. disulphide bonds hold polypeptide chains together